Make InstallOpExecutor take in unique_ptr

Test: th
Change-Id: Ic815eeff654d2943ac6339ae7c991e9e65fad87e
diff --git a/payload_consumer/install_operation_executor.h b/payload_consumer/install_operation_executor.h
index b064cc8..f64318a 100644
--- a/payload_consumer/install_operation_executor.h
+++ b/payload_consumer/install_operation_executor.h
@@ -35,9 +35,9 @@
                                const void* data,
                                size_t count);
   bool ExecuteZeroOrDiscardOperation(const InstallOperation& operation,
-                                     ExtentWriter* writer);
+                                     std::unique_ptr<ExtentWriter> writer);
   bool ExecuteSourceCopyOperation(const InstallOperation& operation,
-                                  ExtentWriter* writer,
+                                  std::unique_ptr<ExtentWriter> writer,
                                   FileDescriptorPtr source_fd);
 
   bool ExecuteDiffOperation(const InstallOperation& operation,